International Commission on Zoological Nomenclature
INTERNATIONAL CODE OF ZOOLOGICAL NOMENCLATURE online

13.1. Requirements. To be available, every new name published after 1930 must satisfy the provisions of Article 11 and must

13.1.1. be accompanied by a description or definition that states in words characters that are purported to differentiate the taxon, or

13.1.2. be accompanied by a bibliographic reference to such a published statement, even if the statement is contained in a work published before 1758, or in one that is not consistently binominal, or in one that has been suppressed by the Commission (unless the Commission has ruled that the work is to be treated as not having been published [Art. 8.7]), or

13.1.3. be proposed expressly as a new replacement name (nomen novum) for an available name, whether required by any provision of the Code or not.

Recommendation 13A. Intent to differentiate. When describing a new nominal taxon, an author should make clear his or her purpose to differentiate the taxon by including with it a diagnosis, that is to say, a summary of the characters that differentiate the new nominal taxon from related or similar taxa.

Recommendation 13B. Language. Authors should publish diagnoses of new taxa in languages widely used internationally in zoology. The diagnoses should also be given in languages used in the regions relevant to the taxa diagnosed.

13.2. Family-group names. To be available, every new family-group name published after 1930 must satisfy the provisions of Article 13.1 and must be formed from an available genus-group name then used as valid by the author in the family-group taxon [Arts. 11.7.1.1, 29].

13.2.1. A family-group name first published after 1930 and before 1961 which does not satisfy the provisions of Article 13.1 is available from its original publication only if it was used as valid before 2000, and also was not rejected by an author who, after 1960 and before 2000, expressly applied Article 13 of the then current editions of the Code.

13.3. Genus-group names. To be available, every new genus-group name published after 1930 (except those proposed for collective groups or ichnotaxa) must, in addition to satisfying the provisions of Article 13.1, be accompanied by the fixation of a type species in the original publication [Art. 68] or be expressly proposed as a new replacement name (nomen novum) [Art. 67.8].

13.3.1. If the name of a genus-group taxon established before 1931 is replaced by a new replacement name (nomen novum) after 1930, the type species of the nominal taxon must then be designated, if one has not already been fixed.

13.3.2. A name published at any time for a collective group [Art. 66] need not be accompanied by a type species fixation, since collective groups have no type species [Art. 42.3.1].

13.3.3. A name published for an ichnotaxon at the genus-group level before 2000 need not be accompanied by a type species fixation; but if such a name is replaced after 1999 by a new replacement name (nomen novum) a type species must then be designated, if one has not already been fixed [Art. 66.1].

13.4. Combined description of new genus-group taxon and new species. The combined description or definition of a new nominal genus or subgenus and a single included new nominal species, if marked by "gen. nov., sp. nov." or an equivalent expression, is deemed to confer availability on each name under Article 13.1.1 (a species-group taxon so described after 1999 must also satisfy the conditions of Article 16.4).

13.5. Combined description of new family-group taxon and new genus. The combined description or definition of a new nominal family-group taxon and a single new nominal genus of which the name provides the basis for the new family-group name [Art. 11.5] is deemed to confer availability on each name under Article 13.1.1, but for such names published after 1930 availability is not conferred on either name unless a type species is fixed for the new nominal genus [Arts. 13.2 and 13.3].

Recommendation 13C. Individual descriptions and definitions. Authors are urged to avoid publishing combined descriptions and definitions. Each new nominal taxon should be differentiated from other taxa at the same rank.